Hemorrhoids are a swollen twisted mass of varicose veins that are located just inside the anus. Hemorrhoids are caused by chronic straining, from constipation, and childbirth. Chronic straining damages the valves located within the veins, and venous blood collects and distends the veins to many times the normal size. The slow flow of blood within the vessel can cause additional injury to the vessel and thrombosis. While rarely fatal, hemorrhoids are painful and treatments can range from heat packs and bed rest (in mild cases), to surgery (in extreme cases). As the patient ages, the elasticity of the tissue of the anus changes and the hemorrhoidal condition can worsen causing prolapse and anal bleeding.
Hemorrhoids can be of two types, external and internal. A ribbed dentate line is located 2.5-3 cm. in from the exterior of the anus and marks the change from the anus to the rectum. External hemorrhoids are found in the anal area below this line and internal hemorrhoids are found in the rectal area above this line. Internal hemorrhoids are generally formed from an internal rectal venous plexus that resides in a submucosal space within the wall of the rectum, approximately 2.5 to 5 cm in from the exterior of the anus. It is a feature of the human anatomy that the venous plexus has three main venous branches or groups located circumferentially around the anus and rectum, and that hemorrhoids usually occur at one or more of these branches. Thus, internal hemorrhoids can protrude from the wall of the rectum in one localized area, more than one localized area, or circumferentially. In severe cases, the internal hemorrhoids can protrude out of the anus.
Internal hemorrhoids are rated by severity from a mild case (first degree) to a much more severe case (fourth degree). First and some second degree cases can be treated by injection or ligation (elastic banding). For the third and fourth degree cases, surgical intervention can be required.
In the past, a wide variety of surgical methods have been suggested for the treatment of severe internal hemorrhoids. The preferred method in the United States is the Ferguson, or closed, hemorrhoidectomy. In the Ferguson procedure, a Ferguson-Hill retractor is inserted into the anus to obtain access to a hemorrhoidal site. The surgeon then clamps the hemorrhoid with alligator clamps, ligates the vessels, and dissects the hemorrhoid from the rectal wall with a scalpel or scissors. Once the hemorrhoid is removed, the surgical site is sutured closed. The retractor is rotated to another position and the remaining hemorrhoids are dealt with in a similar manner.
In general, European surgeons prefer the Milligan-Morgan, or open hemorrhoidectomy for the removal of internal hemorrhoids. In the Milligan-Morgan procedure, rather than using a retractor, the anus is gently dilated with two fingers and forceps are placed at the mucocutaneous junction of each primary hemorrhoid. The hemorrhoids are pulled down and a second forceps is applied to the main bulk of each hemorrhoid to produce "a triangle of exposure". Next, the clamped, hemorrhoid is dissected from the sphincter muscle and is dissected proximally as far as the pedicles and then ligated or tied. Unlike the Ferguson procedure, the wound is not sutured closed, but is left open with a light dressing applied to the wound.
Another hemorrhoidectomy procedure is the Whitehead procedure, which was first performed in 1882. In this procedure, the hemorrhoidal tissue is excised above the dentate line and the redundant rectal mucosa is excised and sutured to the anoderm. This surgery is indicated for circumferential hemorrhoids. Several modifications of Whitehead exist, including raising the anoderm and suturing it to the rectal mucosa. Many surgeons avoid this method as the procedure was thought to be difficult to perform, bloody, and susceptible to complications.
The need for a simple and fast method of performing a hemorrhoidectomy was recognized by Dr. G. Allegra and presented in his 1990 paper entitled "Particular Experience with Mechanical Sutures: Circular Stapler for Hemorrhoidectomy" which was presented to the 1.sup.st. National Conference of the Italian Viscerosynthesis Association in May 28-30, and published in GIORN Chir. Vol. 11- No. 3- pp 95-97, March 1990. This report detailed the use of a conventional circular stapler to perform a hemorrhoidectomy on second and third degree hemorrhoids.
In his paper, Dr. Allegra teaches the use of three fingers to dilate the anus and the placement of a continuous submucosal circle of suture at the base of the pectinate or dentate line. Dr. Allegra also underscores the use of a curved needle to place the suture ring submucosally and stresses that the entry and exit point of the suture be the same or nearly the same.
Next, a conventional circular stapling instrument, having a stapling end effector, is opened by amply extending an anvil assembly away from a stapling head assembly. The opened stapling end effector is placed into the anus of a patient and positioned to place the anvil assembly of the stapling end effector distal to the suture ring and the stapling head assembly (of the stapling end effector) proximally outside the patient. This placement enables the surgeon to reach within the anus and to grasp the loose ends of the suture. The loose ends of the suture are drawn out of the anus and out of the stapling end effector between the open anvil and the stapling head assembly. The loose ends of the suture are then pulled upon to draw the circle of suture closed and to draw the anal tissue in around the anvil shaft connecting the open anvil to the stapling head assembly of the circular stapling instrument. Next, the surgeon tightly knots the suture about the anvil shaft and closes the anvil upon the hemorrhoidal mass. The loose ends of the suture protrude from the stapling end effector between the closed anvil and the stapling head assembly. The stapler is fired to perform the hemorrhoidal transection. Once fired, the circular stapling instrument is removed from the anus with the transected hemorrhoids captured within.
The firing of the circular stapler effectively transects the hemorrhoids and applies staples to the transection site. The use of staples as an effective fastening means is well known in bowel surgery, but not as well known in hemorrhoidal surgery. Studies of 10 cases by Dr. Allegra revealed the hemorrhoidal transection occurs at the submucosal level and does not involve the muscular striae. Thus, the Allegra procedure offers surgeons an alternative to conventional hemorrhoidal procedures such as those developed by Ferguson, Milligan-Morgan, and Whitehead.
Whereas Dr. Allegra did indeed pioneer the use of a circular stapler for hemorrhoidal removal, he was limited by the use of a circular stapler that was optimized for bowel surgery. Circular stapling instruments are well known in the surgical art for bowel surgery and an example of such a device is the ECS 25 Endopath.TM. ILS Endoscopic Curved Intraluminal Stapler from Ethicon Endo-Surgery Inc., Cincinnati, Ohio. Many circular stapler patents exist, for example U.S. Pat. No. 4,207,898 by Becht, U.S. Pat. No. 4,351,466 to Noiles, U.S. Pat. No. 5,292,053 to Bilotti et al., and U.S. Pat. No. 5,344,059 to Green et. al.
One limitation of the Allegra procedure is the depth that the circular stapler can be placed into the anus. As described above, the open anvil assembly of the stapling end effector is placed distal to the suture ring and the stapling head assembly is placed proximally outside the patient. This enables the surgeon to grasp the loose ends of the suture and to draw the suture out of the anus through the gap between the anus and the stapling head assembly. The need for the gap to withdraw the suture from the anus limits the depth that the stapling end effector can be placed into the anus. If the hemorrhoids are located deeper into the anal canal, such as internal hemorrhoids, the stapling head assembly enters the anus and effectively blocks the surgeon from accessing the loose ends of the suture. What is needed is a circular stapling instrument that is not limited to external hemorrhoids but can access hemorrhoids wherever they exist. Such an instrument could effectively be used for the removal of internal hemorrhoids above the dentate line.
An additional limitation of the Allegra procedure is the amount of hemorrhoidal tissue that can be drawn into the stapling end effector of a conventional circular stapling instrument. Hemorrhoids are drawn into and around an anvil shaft (connecting the open anvil assembly to the stapling head assembly) by tightening a continuous loop of suture placed below the dentate line. This action draws the hemorrhoids around the anvil shaft but does not draw the hemorrhoids into the inner chamber of the stapling head assembly. This limits the amount of hemorrhoidal tissue that can be brought into the stapling end effector and the surgeon may remove part of a hemorrhoid. What is needed is a method of drawing the hemorrhoids around the anvil shaft and into the inner chamber of the stapling head assembly to ensure that more of the hemorrhoidal tissue is removed in a single firing of the circular stapling instrument.
Whereas Dr. Allegra describes the use of fingers to dilate the anus during placement of sutures into the hemorrhoidal area, this procedure is tiring and difficult at best. What is needed is a means of dilating the anus during suture placement that does not require the use of a surgeons hand. This would reduce the number of hands required for the surgery and speed up the suturing process. One such means is the use of an anoscope, or speculum, such as those described by Hamilton in U.S. Pat. No. 348,843, by Pennington in U.S. Pat. No. 1,286,083, by Campagna in U.S. Pat. No. 2,922,415, and by Block in U.S. Pat. No. 4,384,067. Whereas these anoscopes were indeed an aid to surgery, they generally provide a pistol grip handle for the surgeon to grasp. The Hamilton patent teaches a pair of generally adjacent handles available for the operation of the instrument. One handle is fixed to the anoscope and is gripped by the surgeon in a pistol grip like manner for rotation of the anoscope within the patient. The second handle is attached to a rotating sleeve within the anoscope, and rotational movement of the handle and the sleeve effectively opens or closes an access slot extending longitudinally down the anoscope body. What is needed is an anoscope that does not provide a pistol grip handle and has an improved handle to facilitate the suturing of the hemorrhoids.
At present, there are no known surgical instruments that can meet all of the needs outlined above. These and other advantages will become more apparent from the following detailed description and drawings.